I've always marveled at how easily Spain was able to conquer these islands. Parang the Spaniards said, "We claim you in the name of the King" tapos natives said, "Sure, watevs."
My history prof friend said it took Spaniards decades to subjugate these islands. The Spaniards who came here after Magellan probably learned the lesson from the survivors. If there was already a central authority by then, it would probably take them less than a year.
Plus, before they came each island/baranggay is a different territory, oftentimes hostile against each other